Contour grinding apparatus



R. A. HINKLEY Em 2,290,051 CONTOUR GRINDING APPARATUS Y 2 Sheets-Sheet l Filed on. 5; 1959 T0 HYDRAULIC. FLU/D PUMP MOTOR INVENTOR in? 14. Hay/(5Y n/u: flLTEE C bkEEk "@k okiw'sx July 14, 1942. R. A. HINKLEY ET AL I CONTOUR GRINDING APPARATUS Filed 001:. 5, 1939 2 Sheets-Sheet 2 INVENTORS. A

v FAY film/us) mm WALTER C. WEBEa RNEY:

' but adjustable speed, and

Patented Ju ly 14, 1942 Bay A. Hinkley, comm Weber, Corning ration of New York s. N- West Hartford, Glass Works Y., and Walter C.

nn., assignors to I Corning, N. Y., a corpo- Application October 5, 1939, Serial Nascent 9 Claims.

The present invention relates to grinding and polishing methods and apparatus and particularly to grinding machines capable of doing precision grinding of work to a desired contour.

Such work has been ground in'the past by 4 subjecting it to an abrasive wheel, the face of which has previously been dressed to the exact contour to be imparted to the work-piece. This form of apparatus has the drawback that if the contour of the work-piece is such that it is held stationary while its entire surface is simultane- -ously contacted by the abrasive wheel, grooving is likely to result, whereas if the Work-piece surface contour is such that the work-piece can be rotated as the work wheel advances across the work-piece, elaborate work-wheel shifting and precision apparatus is required to frequently redress the work-wheel to the exact contour it is to impart to the work-piece. In order to reduce theamount of equipment to a minimum, applicants have designed a machine capable of doing precision contour grinding with a work-wheel having a flat work surface, which although also requiring frequent redressing of the work-wheeL'has the advantage-that a flat surfaced wheel is employed which can be dressed with comparatively simple equipment.

The prime object of the a grinding and/or polishing extremely accurate work and yet is practicable and eflicient.

the present invention is a contour grinding and/or polishing machine a flat work surface rather than one .shaped'to the contour to which the work-piece is to be ground.

present invention is machine which does' employed in pressing glass into shapes suitable for use as reflectors in automobile head light units and similar applications;

. Fig. 2 is a front elevation of the apparatus; Fig. 3 is an end elevation 'ofthe apparatus;

Fig. 4 is a view taken on line 1-4 of .Fig. l;

and a Fig. 5 is a sectional view taken on line 5-5 of Fig. 1.

carriage 83 has a rack formed on The invention embodies among its features a movement of the work-wheel over a path corresponding to the precise contour to which the work-piece is to be finished. I Other objects and features of the invention will become apparent from a further perusal of the specification and. the accompanying drawings.

Fig. 1 of the drawings is a plan view of a preferred form of apparatus embodying the invention as used in grinding plungers such as are The variousworking parts of the apparatus are mounted on a suitable-upright H having a laterally extending V-grooved bed l2 (Fig. 3) for supporting a carriage 13. This carriage carries a work supporting and rotating assembly generally designated l6 comprising a workpiece spindle I! (Fig. 2) driven by a belt connected motor l6 (Figs. 1 and 3) and carrying a work-piece face plate or chuck I6 (Fig. 2).

thereof which is in mesh with a gear 20 (Fig. 3) adapted to be rotated by a hand wheel 2|, thereby enabling movement of the unit 5 as required to bring a work-piece 22, mounted in the chuck l9, into proper position with respect to the working surface of a work-wheel 23 of a grinding or polishing unit 25.

The grindingunit 25 is suspended froma slide 26 (Figs. 1 and 2) by means of a column 21. The slide 26 is ing screw 80. The frame 28 has three pads 3| on the under surface thereof which rest on a fiat I table or bed 32iigidly mounted on the upright l I. The frame 28 is slidable on the surface of table 32, but its range of movement is definitely and by a properlycontoured also igidly mounted on the of the plate 36 is such that 23 isat all times perpendicular to a tangent at any point on the work-piece 22 with which it is in point contact.

The frame 28 is held in predetermined relation with respect to cam 35 by a pair of rollers fulcrum plate 36 bed. The contour the grinding wheel mounted in a frame 28 in which it is slidably adjustable by means of an adjustsuch that it holds roller 40 tightly against the cam 35. ,A pressure regulating valve fls-is provided in the fluid supply line to unit 31 so as to enable just the proper amount of pressure to be applied to overcome am! side play in the assembly as the unit 25 travels over the path defined by the contour of cam 35. oscillatory movment of the unit is effected by means of a piston rod ii of a hydraulic power unit 52. Operating fluid is alternately suppliedto the opposite ends of unit 52 from fluid supply line 55 under control of an electromagnetically actuated valve 56. Magnets 51 and 58 of this valve are alternately energized to actuate the valve upon closure of contacts 52 and N in their respective circuits at the end of a travel of the piston rod 5i. A regulating valve 6| enables adjustment of the pressureapplied to unit 52. The fluid feed lines to unit 52 are also supplied with valves 53 and 54 so that the speed of movement of the unit can be modified as desired.

The adjustment of the work-wheel with respect to a work-piece is effected by first bringing the face of the work-wheel in a position normal to the axis of the work-piece, as shown in-Fig. 1. This is accomplished by opening switch 82 in the circuit of magnet 58 so thatthe magnet 58 will remain deenergized after contacts I! are closed and, accordingly, the supply of operatingfluid to the front end of wit 52 is prevented. With the work-wheel 22 in the position shown, handle 2| is rotated as'required to bring the work 22 within a predetermined distance of cam 35 as determined by a suitable gaugellprovided for this purpose. The adjusting screw 30 is then manipulated to bring the work-wheel 21 in contact with the work 22. A gauge 66 carried by slide 2G,and cooperative with a stop on the frame 28 affords a convenient means of setting the work wheel to obtain the amount of cut desired.

After the foregoing adjustments have been made the machine is started by closing switches V 83 and GI through which operating current is supplied to, motors l8 and ll, of the work piece supportlng/ andgrlnding units respectively. and by closing contacts 62 to enable energization of magnet 58. 4

As will be evident, the contour of the flnished work-piece is primarily determined-by the contour of cam 25. Toinsure the highest degree of accuracy. however,the contour of fulcrum plate 36 is such that the pivot point of the frame 28 is always such as to maintain the working surface of the work-wheel 23 normal to the surface being ground. To grind a work-piece of a different contour than illustrated, suitable cam and plate elements, flnished to the contour desired. are substituted for the illustrated and 38. I

It will be observed from the draWinS that rinding wheel 2: is of substantial thickness.- However. as will be appreciated, with the face.

of the wheel arranged at right angles to the axis of the vwork-piece 'only' a minute width of the wheel face is actually, brought into contact with the work-piece, It is entirely possible therefore to employ a: much thinner wheel than that shown. It has been found, however, that a wheel of substantial thickness is' preferable since it can be operated with'greater-precision due to its freedom from vibration.

, While in the foregoing there has been shown and described the preferred embodiment of our invention, it is to be understood that minor elements I bination of parts may be resorted to without departing from the spirit and scope of our invention as claimed.

- What is claimed is:

5 1. In a machine for precision grinding of irregularly contoured surfaces of revolution, a support for rotating a blank about its longitudinal axis, a rotatable work-wheel, support means for said work-wheel including a plain horizontal 10 surface parallel to and spaced from said axis and a wheel mounting, means for oscillating said mounting on said surface and control means located at spaced points for determining the path of movement of said mounting on said surface,

one of said control means comprising an accurately contoured cam engaging said mounting adjacent the point of attachment of said oscillating means, another of said control means comprising an accurately contoured cam engag- 2 ing a flat surface on said mounting means remote from the point of atacliment of said oscillating means.

2. In a machine for precision grinding of irregularly contoured surfaces of revolution, a support for rotating a blank about its longitudinal axis, a table, a rotatable work-wheel, a support for said work-wheel resting on but unattached to said table. means for sliding said support over the surface of said table, a cam fixed to the upper surface of said table, means for holding said support in engagement with said cam at all times to .conflne and guide the movement of said support to an accurately determined course corresponding to the gene'ratrix for the desired surface of revolution, and a second cam cooperative with said work-wheel support to change the angular position of the axis of said work-wheel with respect to the axis of said work-piece support as required to maintain the same peripheral surface 0 area of the work-wheel in contact with the work-piece at all times.

3. In a machine for precision grinding of irregularly contoured surfaces of revolution, a support for rotating 9. blank about its longitudinal axis,- a mounting having lateral extensions and a a rotatable work-wheel arranged intermediate the extensions, a table for supporting said mounting having a plain top surface upon'which said mounting rests. means for oscillating the mount ing on the table surface, means located at spaced points on the surface of said table for determining the path of movement of said mounting on said surface, one of saidmeans comprising an accurately contoured cam cooperative with one of the lateral extensions of said mounting to change the angular position of the axis of the work wheel with respect to that of the support for the blank.

4. In a machine for precision grinding of irregularly contoured surfaces of revolution, a support for rotating a blank about its longitudinal axis, a mounting having a surface for engagement with a guide cam andcarrying a rotatable work-wheel, a table having a plain top surface 85 upon which said mounting rests, means attached to said mounting for oscillating the portion thereof to which it is attached over the surface of said table, means located at-spaced points'o'n said table for determining the path of movement of such attached portion of said mounting on said table, one of said means comprising an accurately contoured guide cam fixed to said table and about which said mounting surface rocks during the oscillation of the portion of the changes in -the details of construction and commounting to which said oscillating means is attached, and means for maintaining a surface of said mounting in engagement with said cam.

5. In a contour grinding machine, a table having'fixed thereon a cam track with a surface of a contour determined by the contour to be produced on a work-piece, a grinding unit'slidably supported on said table, hydraulic means attached to onepart .of said grinding unit for maintaining such part in permanent engagement with said cam track, hydraulic means for moving such part to and fro between opposite ends of said cam track, anda cam plate fixed to-said table having-a surface about which another part of said grinding unit fulcrums as the one part thereof moves to and fro.

6. In a machine for the precision grinding of irregularly contoured surfaces of revolution, a support for rotating a blank about its axis, a rotatable work-wheel, support means for said work-wheel including a fixed table having a plain horizontal top surface with a wheel mounting support properly fixed with respect to the axis of the wheel and resting on the referred to table surface, hydraulic means for oscillating one lateral extremity of said mounting between predetermined spaced positions on said surface, means for guiding said mounting during its movement between such positions over a path depending on the contour to be imparted to the blank, means about which said support fulcrums during its movement between said spaced positions and hydraulic means for maintaining said support in contact with said last two means at all times.

7. In amachine of the character described, a 4

support for rotating a blank about its longitudinal axis, a rotatable work-wheel, a mounting for said wheel having parts extending laterally in opposite directions therefrom, a table having a plain horizontal surface upon which said mounting rests, means for oscillating one part of said mounting between predetermined spaced points on the table surface, means cooperative with such part to determine the path of travel thereof in the course of its movement between 5 said points, and other means cooperative with I the other part of said mounting to determine its path of travel during the movement of the first part between said points.

8. In a machine for grinding an article with a paraboloidal surface, a support having a workwheel thereon, a support for the article, means for bringing the work-wheel surface and a surface of the article into a predetermined contactual relation, means for rotating said article support and said work-wheel, means for shift- 5 nal axis, a support equipped with a rotatable work-wheel, means having a plain horizontal surface upon which one of said supports rests, means for oscillating said one support over said surface, control means located at spaced points for determining its path of movement thereover,

one of said controlmeans comprising an accurately contoured cam engaging the oscillated support adjacent the point of attachment of said oscillating means, another of said control means comprising an accurately contoured cam engaging a flat surface on such support remote from the point of attachment of said oscillating means.

RAY A. HINKLE'Y,

5 WALTER c. WEBER. 

